It is known that various kinds of processing is performed based on mechanism computer aided design (CAD) data that are used by a CAD system, which is also referred to as a mechanism CAD system or a mechanical CAD system. For example, techniques for checking electrical conduction between mechanism parts of an electronic information device using mechanism CAD data are known (for example, refer to Japanese Laid-open Patent Publication No. 2009-205202). Also, techniques for comparing a plurality of mechanism CAD data in order to mechanically detect a product having a similar shape to that of a desired product from previous design data are known (for example, refer to Japanese Laid-open Patent Publication No. 2001-307111).
When various devices are designed, electrical design, in which a printed circuit board that functions as a control unit for controlling a device is designed, and mechanism design, in which the overall structures of the mechanism parts other than a printed circuit board are designed, are sometimes carried out in parallel with each other. Electrical design includes specification design, in which the specification of a printed circuit board is designed, circuit design, in which a circuit that realizes the specification designed by the specification design is designed, and implementation design, in which the circuit designed by the circuit design is implemented on a printed circuit board. In electrical design, such as circuit design, implementation design, and the like, an electrical CAD system is used as a design tool.
Mechanism design includes shape and structural design in which the shapes of mounted parts are designed, size and material design in which the size and the material of the mounted parts are designed, and cooling and noise analysis in which the heat generation state of the device and electromagnetic noise are analyzed, and the like. In mechanism design, a structural CAD system is used as a design tool.
In recent years, parts mounted on a device have a higher density of integration and are miniaturized due to technical advancement of the device, and the signal speeds have become faster. Consequently, the gap interference condition between a printed circuit board and parts placed on the periphery of the printed circuit board becomes severe. Accordingly, there is a risk of the occurrence of a short circuit in a device made on an experimental basis. An electrical designer checks whether or not a part mounted on a device is in contact with a conductive element placed on the printed circuit board, whether or not a part in contact is a conductor, and whether or not a conductor in contact is intentionally in contact, and the like in order to avoid the occurrence of a short circuit.
An electrical designer imports a three-dimensional model for indicating the shape information of the parts designed by a structural CAD system and placement information into an electrical CAD system, and gives net information for indicating connection relationships with the printed circuit board and the elements on the printed circuit board to the parts in contact with the printed circuit board, or the like. An electrical CAD system checks the presence or absence of a short circuit of the parts with a printed circuit board and the elements on the printed circuit board based on the net information given by the electrical designer.
However, specifications are often changed during the design both in electrical design and mechanism design, and there is a risk of not transferring a change of specifications, which are usually transferred using a specification document, or the like between an electrical designer and a mechanism designer. If a change of specifications is not transferred between an electrical designer and a mechanism designer, there is a risk that the electrical designer might not be aware of a change in the electrical connection due to the design change in the mechanism design. For example, if a connection material, such as a screw, a bolt, a boss, or the like that has connected a ground wiring line of a printed circuit board and a metal plate is deleted due to a design change in mechanism design, the connection between the ground wiring line of the printed circuit board and the metal plate becomes open. In an electrical CAD system, it is possible to check the presence or absence of a short circuit, but it is not possible to check the presence or absence of open. Accordingly, there is a risk that it is not possible for the electrical designer to find that the ground wiring line of the printed circuit board and the metal plate are not connected.
According to an embodiment, it is desirable to provide an electrical design support program that makes it easy to detect a change of net information for indicating the electrical connection relationship between parts to be mounted on a device and a printed circuit board and the elements placed on the printed circuit board when there is a design change in mechanism design.